Enzymes are often found in infectious bacteria typically having a molecular weight of under 50,000, and which enzymes antagonize the antibacterial action of antibiotic drugs. For example, penicillinase, a beta-lactamase, is often found in infectious bacteria and which causes the enymatic breakdown of beta-lactam-type drugs used to treat that bacteria, such as penicillin. Thus, before an infection for a microorganism or a bacteria can be treated, it is typically advantageous to determine from a sample of a body fluid whether or not the microorganism generates a beta-lactamase, so as to determine whether the infection from the microorganism or bacteria may be treated with a beta-lactam-type drug. If a microorganism contains penicillinase, then the infection cannot be treated with a penicillin or a penicillin-type beta-lactam antibiotic drug that can be destroyed by the beta-lactamase.
Presently available methods for detecting beta-lactamase in microorganisms are not wholly satisfactory and are not rapid techniques. One method comprises culturing the microorganism and determining its resistance to the beta-lactam drug which method takes from 24 to 48 hours. Another method involves determining beta-lactamase by employing column chromatography. This test method takes about 2 hours. The need for the rapid diagnosis of infections caused by beta-lactamase in bacteria and the difficulties caused by the presence of beta-lactamase in bacteria is set forth for example in an article of The Journal of Pediatrics in November 1980 by R. H. Yolken et al. In this publication there is proposed a rapid diagnosis of infections caused by beta-lactamase producing bacteria by means of an enzyme radioisotopic assay technique. In the proposed test both penicillin (a beta-lactam drug), and beta-lactamase give positive tests in the proposed test.
The receptor for beta-lactam drugs is on a microbial cell which is a second reagent in the assay. If a beta-lactamase is present in the fluid to be tested, it destroys the C.sup.14 penicillin used in the assay by degrading the beta-lactam ring. This prevents the binding of the C.sup.14 penicillin reagent to the receptor site on the microorganism reagent. Unlabeled penicillin in the sample also prevents C.sup.14 penicillin from binding to the receptor sites by competition for these sites. Thus, the presence of both beta-lactamase and a beta-lactam drug in the test sample results in low C.sup.14 attachment to the microbial receptor making for a positive test result. If beta-lactamase or penicillinase is present, this test signals that a beta-lactam drug is not useful for treatment when the beta-lactamase is present.
Thus, it is desirable to provide a method for the detection of beta-lactamase, (such as penicillinase) in infectious causing microorganisms and bacterias so as to provide an easy, simple, and rapid test to distinguish between penicillinase and penicillin.